At present, terminal devices (for example, mobile phones) detect pressure caused by touches of users' hands by using a pressure sensor generally. As illustrated in FIG. 1A, a conventional pressure detection structure of a terminal device includes a cover 1, a middle frame 4, a display screen 2 and a pressure sensor 3. The pressure sensor 3, the display screen 2 and the cover 1 are sequentially stacked in the middle frame 4 from bottom to top. The pressure sensor 3 is fixed to a bottom of the middle frame 4, and a gap 5 is formed between the pressure sensor 3 and the display screen 2. Generally, the pressure sensor 3 is a capacitive sensor, and as illustrated in FIG. 1B, includes a substrate 6 and detection electrodes 7 arranged in a matrix form on the substrate 6. The detection electrodes 7 of the pressure sensor 3 and an external reference electrode form the capacitances as illustrated in FIG. 1C. Each of the detection electrodes 7 on the substrate 6 forms a capacitance C with a reference electrode 8. In the pressure detection structure as illustrated in FIG. 1A, the reference electrode is an internal electrode of the display screen, wherein the structure of the capacitor thereof is as illustrated in FIG. 1D. Pressure detection is practiced as follows: when a force is applied to the cover 1, the cover 1 deforms, such that the spacing between the pressure sensor 3 and the display screen is changed, and thus the capacitance between the pressure sensor 3 and the reference electrode is changed. Accordingly, the pressure is identified according to the variation quantity of the capacitance.
As seen from the implementation principle, a detection spacing between the display screen 2 and the pressure sensor 3 needs to be well controlled, wherein the detection spacing is the gap 5 as illustrated in FIG. 1A. However, the gap 5 is subject to complicated and more working processes and masses of parts to be assembled during the mass production, and thus the assembling is subject to a great tolerance. In addition, the tolerance of the spacing between the display screen 2 and the middle frame 4 of different machines may affect consistency of the machines, and thus the user experience is different between the different machines. Moreover, falloff and extrusion-caused deformation of the entire product may simply change the gap, thereby lowering reliability of the products.